What you quoted is for bundling, or without a raceway.
My bad. It is still there just a few lines down from where I posted.
(C) Adjustment Factors.
(1) More than Three Current-Carrying Conductors.
The ampacity of each conductor shall be reduced as shown in
Table 310.15(C)(1) where the number of current-carrying conductors in a raceway or cable exceeds three, or where single conductors or multiconductor cables not installed in raceways are installed without maintaining spacing for a continuous length longer than 600 mm (24 in.). Each current-carrying conductor of a paralleled set of conductors shall be counted as a current-carrying conductor.
Where conductors of different systems, as provided in
300.3, are installed in a common raceway or cable, the adjustment factors shown in
Table 310.15(C)(1) shall apply only to the number of power and lighting conductors.
Informational Note No. 1:
See Informative Annex
B for adjustment factors for more than three current-carrying conductors in a raceway or cable with load diversity.
Informational Note No. 2:
See
366.23 for adjustment factors for conductors and ampacity for bare copper and aluminum bars in auxiliary gutters and
376.22(B) for adjustment factors for conductors in metal wireways.
- (a)
Where conductors are installed in cable trays, 392.80 shall apply.
- (b)
Adjustment factors shall not apply to conductors in raceways having a length not exceeding 600 mm (24 in.).
- (c)
Adjustment factors shall not apply to underground conductors entering or leaving an outdoor trench if those conductors have physical protection in the form of rigid metal conduit, intermediate metal conduit, rigid polyvinyl chloride conduit (PVC), or reinforced thermosetting resin conduit (RTRC) having a length not exceeding 3.05 m (10 ft), and if the number of conductors does not exceed four.
- (d)
Adjustment factors shall not apply to Type AC cable or to Type MC cable under the following conditions:
- (1)
The cables do not have an overall outer jacket.
- (2)
Each cable has not more than three current-carrying conductors.
- (3)
The conductors are 12 AWG copper.
- (4)
Not more than 20 current-carrying conductors are installed without maintaining spacing, are stacked, or are supported on “bridle rings.”
Exception to (4):
If cables meeting the requirements in
310.15(C)(1)(d)(1) through (C)(1)(d)(3) with more than 20 current-carrying conductors are installed longer than 600 mm (24 in.) without maintaining spacing, are stacked, or are supported on bridle rings, a 60 percent adjustment factor shall be applied.
